Dosing pump operating in opposite phases for dosing liquid or gaseous media



June 27, 1967 s. DUINKER ETAL 3,327,633

DOSING PUMP OPERATING IN OPPOSITE PHASES FOR DOSING 1 LIQUID OR GASEOUS MEDIA Filed Feb. 12, 1965 2 Sheets-Sheet 1 FI'J H 3 I & v Q -& a q I W. 8 a 9 W n. 1 n n W 9 m 5 7% 9 w. 1 Q 5 y a a 3 A 7 7 INVENTOR SIMON DUINKER 4" DIETER GOSSEL AGENT June 27, 1967 s. DUINKER ETAL 3,327,633

DOSING PUMP OPERATING IN OPPOSITE PHASES FOR DOSING LIQUID OR GASEOUS MEDIA 2 Sheets-Sheet 2 Filed Feb. 12, 1965 INVENTORJ smou oumxsmy 01s T'ER a AGENT United States Patent 3,327,633 DOSING PUMP OPERATING IN OPPOSITE PHASES FOR DOSING LIQUID 0R GASEOUS MEDIA Simon Dninker, Hamburg-Bahrenfeld, and Dieter Gossel,

Hamburg-Lump, Germany, assignors to North American Philips Company, Inc., New York, N.Y., a corporation of Delaware Filed Feb. 12, 1965, Ser. No. 432,139 Claims priority, application Germany, Mar. 7, 1964, P 33,785 3 Claims. (Cl. 10338) The invention relates to a dosing pump operating in opposite phases for dosing liquid or gaseous media with displacers, which are sealed with respect to the housing of the pump by means of flexible diaphragms, which are supported, on the side remote from the operating space, by an incompressible medium.

Piston-dosing pumps have a large stroke volume and an associated large delivery. This large stroke volume and the associated large delivery are based on a favorable ratio of the stroke volume to the so-called dead space. The name dead space is given to that part of the cylinder contents which is not reached by the piston during its movement and which is consequently not emptied during a stroke. Therefore, the displacing stroke only depends on the pressure to a small extent.

In piston-dosing pumps, the inevitable leakage losses along the stufiing boxes of the pistons, which occur in particular with low delivery and with media with 10W 'viscosities, are disadvantageous and reduce the accuracy.

In addition, the medium to be pumped comes in contact ,with the sealing parts of the piston and the stufiing boxes.

Diaphragm dosing pumps are used when, usually as a result of the properties of the medium to be dosed, a

construction must be used without stufiing boxes. In

.these pumps no leakage losses occur.

In the known diaphragms, the stroke is obtained by flexible deformation of the diaphragm, the tension increasing with the stroke. In order to obtain a reasonable life of the pump, consequently only short strokes may be permitted, as a result of which the ratio of the stroke .volume to the dead space becomes unfavorable. In this case the accuracy is no better than that of piston pumps. In addition, the delivery is only low in relation to the size of the pumps. Finally it is necessary to replace the heavily loaded diaphragm, which. is. subject to wear, at regular intervals.

In compressors it is known to seal the compression chamber by means of flexible diaphragms, so-called rolling diaphragms. In this case the rolling diaphragms are either forced against the wall of the housing only in which they engage a movable piston in the shape of a flattened hose, or they are connected in the housing and to the piston. During the strokes of the piston the diaphragm rolls along with the piston. In order to give the diaphragm the required resistance and sealing power, the hollow space below the diaphragm is in addition filled with an incompressible liquid.

The said drawbacks of the known dosing pumps are avoided in a dosing pump operating in opposite phases according to the principle of the piston pump for dosing liquid or gaseous medium with pistons which are sealed with respect to the housing of the pump by means of rolling diaphragms which are supported, on their side remote from the operating space by an incompressible medium. Therefore, the pistons connected to the same shaft are connected by means of a sliding member, which is journalled in the housing of the pump, and the rolling diaphragms, which separate the operating chambers from the bearing in the housing, are connected at one end along the end edges of the pistons and at the other end,

3,327,633 Patented June 27, 1967 approximately at half the height of the stroke, to the cylinder Walls. The pistons have a smaller diameter with respect to the sliding member and in the direction thereto so that the sealing chambers between the diaphragms and the sliding bearing have the same volume at any position of the pistons.

The dosing pump according to the invention operate in opposite phases distinguishes from the known pumps in that with long stroke and small dead space no leakage losses occur in this pump. This is the result of the fact that the incompressible medium which supports the diaphragms is provided in a completely closed hollow chamber which is divided by the bearing in only two parts and which has no passages to the outside. A small migration of the medium from the sealing space of one cylinder to the sealing space of the other is compensated by an equally large opposite migration during a movement of the piston in the opposite direction, so that thereby no error can occur.

In contrast with the known pump diaphragms, the load of the rolling diaphragms in the pump according to the invention is extremely small because these diaphragms are mainly uncoiled only and thereby subjected to very small flexible loads only. Moreover, the load of the diaphragm is entirely independent of the extent of the stroke.

As a result of the smaller load, the life of the diaphragms in the pump according to the invention increases. Whereas in known diaphragm dosing pumps with a small stroke a life is stated of 4500 hours at 108 strokes per minute, which corresponds to approximately 3 10 strokes totally, the pump according to the invention with rolling diaphragms still operates excellently after more than 10,000 operating hours at 1500 strokes per minute, which corresponds to 9X10 strokes totally and a length of stroke of 65 mm. The life of the rolling diaphragm in the pump according to the invention consequently is at least 30 times as large as the life of the diaphragm in a diaphragm dosing pump of the conventional construction.

The dosing pump according to the invention is preferably driven electromagnetically. The pistons with the sliding member connecting them as well as the sliding bearing and movable stop members for varying the volume of the stroke consist of a magnetically readily conducting material, whereas the remaining parts of the pump are manufactured from magnetically poorly conducting material. The pistons in the dosing pump according to the invention are reciprocated through energizing coils which are provided on iron yokes which connect the bearing and the stop members by means of the field forces, which are the result of the currents flowing through the energizing coils. In this manner any mechanical connection between the operating chambers for the pistons and the surroundings is lacking so that the problems involved in stufiing boxes are omitted.

In order that the invention may readily be carried into effect it will now be described in greater detail with reference to the accompanying drawings in which FIG. 1.diagrammatica lly shows an embodiment of an electromagnetically driven dosing pump according to the invention operating in opposite phases, the piston being in the lowermost final condition.

FIG. 2 shows the pump according to FIG. 1, the piston being in the uppermost final position.

FIG. 3 shows the pump according to FIG. 1 with a stroke reduced by a stop member.

FIG. 4 diagrammatically shows the electromagnetic drive of the pump according to the invention for operation which is independent of the direction of current.

FIG. 5 shows an electromagnetic drive for operation which is dependent upon the direction of current.

Referring now to FIG. 1, the dosing pump which operates in opposite directions consists of a housing 1 comprising a sliding bearing 3 for a piston 5 which consists of a sliding member 7 and two oppositely located pistons 9 provided on the sliding member 7. The piston is guided in the sliding bearing 3 and is capable of displacing gaseous or liquid media contained in cylinders 11 which are located on both sides of the sliding bearing. Rolling diaphragms 15 are attached to the end faces 13- of the pistons. In addition these rolling diaphragms engage the cylinder walls 17 approximately at half of the length of stroke.

The sealing chambers 19 between the rolling diaphragms 15 are filled with an incompressible liquid. They are substantially equal at any position of the stroke of the piston 5. This is reached in that the pistons have a reduced diameter over parts of their cross-section, which parts can be moved exactly up to the sliding bearing 3 during the stroke movements, in which the cylinders, preferably also up to the sliding bearing, have a diameter which is larger than the cross-section of the sliding bearing so that the formed annular surfaces are equal to one another.

The volumes of the chambers 11 of the cylinders can be adjusted by means of stop members 21. In the position of the cylinders shown in FIG. 3 one of the stop members 21 is screwed into a cylinder chamber 11 through a given distance.

The medium to be displaced flows through the chambers 11 through a feed-pipe 23 provided on the housing of the pump and through pipes 25 joining this feed pipe. In accordance with the direction of movement of the pistons 5, the medium to be displaced is conducted away from the upper or lower chamber 11 through pipe 27 and a-n outlet pipe 29. Check valves 31 in the pipes 25 and 27 ensure that the displaced medium cannot flow back erroneously.

As shown in FIGS. 1 and 2, the spaces 33 in the pump according to the invention are extremely small since the end faces of the pistons engage the stop member 21 provided in the housing of the pump 1 and only annular spaces remain which the rolling diaphragms leave as a result of their construction.

In the pump according to the invention the piston construction is operated electromagnetically.

For this purpose the stop members 21, the sliding bearing 3 and the piston 5 are manufactured from magnetically conducting material. The sliding bearing and the stop members are connected together by means of soft magnetic iron yokes 35 (FIG. 4.). As a material for the yokes is to be considered iron or ferrite. Energizing coils 37, 38 are connected to the yokes 35 and are provided with a current by a voltage source 41, at choice and alternately, by means of a switch 39. In accordance with the position of the switch 39 the current from the direct voltage or alternating voltage source 41 flows through the winding 37 or through the winding 38. Since the magnetic forces in this case are so operative that they try to reduce the magnetic resistance in the circuit energized at that instant, independent of the direction of the magnetic field, the piston construction 5 is attracted by one or by the other pole shoe 21.

In operation, in accordance with the direction of current shown in FIG. 5, the piston construction 5 is magnetized. In this case one end face of the piston has a magnetic south pole 43 and the other end face of the piston has a magnetic north pole 45. By reversing the polarities of the windings 37 and 38 fed by a direct current source 47 by means of a switch 49, the direction of the driving force acting upon the piston construction 5 is varied.

Instead of through the switch 49, the windings 37 and 38 may also be supplied directly from a current source with alternating polarity. In this case alternating current or pulse current sources are to be considered. In that case below the limit frequency of the pump the delivery is determined by the frequency of the supply source. This is particularly favorable for dosing devices in which it must be possible to vary the delivery during operation. When several dosing pumps according to the invention operate in parallel with each other and are driven while shifted in time with respect to each other, it is also possible to effect a fully continuous transport.

What is claimed is:

1. A pump operating in opposite directions for supplying liquid or gaseous media, said pump having a pair of axially spaced pistons, a housing for said pistons, flexible diaphragms connecting said pistons to said housing, an operating chamber for each of said pistons, an incompressible medium supporting each of said flexible diaphragms on a side thereof remote from said operating chamber to form an annular sealing chamber wherein the improvement comprises a sliding member journalled in said housing and connecting said pistons, said flexible diaphragms separating said operating chambers and each being connected on one end to the adjacent end face of said piston and at the other end to the adjacent housing wall, said pistons having a reduced diameter with respect to said sliding member, said slidable member when operative entering said sealing chamber to thereby displace said medium in an amount equal to the change in the configuration of said chamber whereby the net volume of said chamber remains constant.

2. A pump as claimed in claim 1 further comprising a sleeve-like bearing in said housing, said sliding member being rectil-inearly movable therein, and said sliding member and piston being circular in cross-section and movable in said annular sealing chamber.

3. A pump as claimed in claim 1 further comprising movable stop members which are adapted to vary the volumes of their respective operating chambers; said movable stop members and sliding member being constituted of magnetically conducting material, and further comprising a magnetic yoke connecting said stop members and said sliding member together, and means for providing an electrical current to said yoke whereby said pistons are magnetized and are selectively moved.

References Cited UNITED STATES PATENTS 2,191,861 2/1940 Rymal 103-148 2,342,906 2/1944 Smith 103-148 2,576,747 11/1951 Bryant 103-38 2,686,280 8/1954 Strong 103-53 2,943,577 7/1960 Barker 103-148 2,952,218 9/1960 Stefies 103-152 3,099,260 7/1963 Birtwell 103-148 3,134,938 5/1964 Morgan 103-53 3,204,858 9/1965 Dros 230-49 3,227,093 1/1966 Taplin 103-150 DONLEY J. STOCKING, Primary Examiner.

LAURENCE V. EFNER, Examiner.

W. L. FREEH, Assistant Examiner. 

1. A PUMP OPERATING IN OPPOSITE DIRECTIONS FOR SUPPLYING LIQUID OR GASEOUS MEDIA, SAID PUMP HAVING A PAIR OF AXIALLY SPACED PISTONS, A HOUSING FOR SAID PISTONS, FLEXIBLE DIAPHRAGMS CONNECTING SAID PISTONS TO SAID HOUSING, AN OPERATING CHAMBER FOR EACH OF SAID PISTONS, AN INCOMPRESSIBLE MEDIUM SUPPORTING EACH OF SAID FLEXIBLE DIAPHRAGMS ON A SIDE THEREOF REMOTE FROM SAID OPERATING CHAMBER TO FORM AN ANNULAR SEALING CHAMBER WHEREIN THE IMPROVEMENT COMPRISES A SLIDING MEMBER JOURNALLED IN SAID HOUSING AND CONNECTING SAID PISTONS, SAID FLEXIBLE DIAPHRAGMS SEPARATING SAID OPERATING CHAMBERS AND EACH BEING CONNECTED ON ONE END TO THE ADJACENT END FACE OF SAID PISTON AND AT THE OTHER END TO THE ADJACENT HOUSING WALL, SAID PISTONS HAVING A REDUCED DIAMETER WITH RESPECT TO SAID SLIDING MEMBER, SAID SLIDABLE MEMBER WHEN OPERATIVE ENTERING SAID SEALING CHAMBER TO THEREBY DISPLACE SAID MEDIUM IN AN AMOUNT EQUAL TO THE CHANGE IN THE CONFIGURATION OF SAID CHAMBER WHEREBY THE NET VOLUME OF SAID CHAMBER REMAINS CONSTANT. 